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The ability to accurately and precisely measure gas volume and gas flow is a fundamental component in the safe provision of modern anaesthesia. This is vital for the delivery of gasses and monitoring of respiration. A range of techniques are used to measure gas volume and flow, both by direct and indirect measurement. Direct methods of gas volume measurement tend to be large and impractical. By using physical properties of gases indirect measurements can be made. Understanding the principles of these techniques allows interpretation of the data they produce. Descriptions of devices used in anaesthetic practice are given. These devices include the variable orifice flowmeter, differential pressure flowmeter, hot wire anemometer, mechanical flow transducer, ultrasonic flowmeter, Wright respirometer, Vitalograph and peak flowmeter. [ABSTRACT FROM AUTHOR]

Measuring the flow rate in High-Temperature Gas-cooled Reactors is a challenge for traditional flowmeters due to the high flow rate (10 to 15 m/s at nominal operating conditions), high operating temperatures (>700°C), and high neutron flux and gamma fields in the reactor core. This paper discusses developing a novel flowmeter that can work under these extreme conditions. Oak Ridge National Laboratory first proposed using acoustics to measure the flow in the reactor, more specifically, using a Kelvin-Helmholtz resonator to correlate the gas flow rate with vibration frequency. With the primary goal of developing an acoustic measurement technique, we propose an acoustic corrugated pipe as a candidate for the development of a novel gas flowmeter. Experimental investigations on corrugated pipes have confirmed the dependence of the whistling frequency on the gas flow rate. Also, a tube-in-tube configuration is proposed for the flowmeter prototype, which can help mitigate resonance between the system and the flowmeter. Experimental investigation using the prototype has shown good independence from the piping system. Furthermore, Unsteady Reynolds-Averaged Navier-Stokes (URANS) simulations have been performed and validated with a satisfactory agreement, providing confidence that URANS models can adequately predict the characteristic curve (flow rate versus frequency) of the corrugated pipe and can therefore be used to optimize the flowmeter designs cost-effectively. [ABSTRACT FROM AUTHOR]

The ability to accurately and precisely measure gas volume and gas flow is a fundamental component in the safe provision of modern anaesthesia. This is vital for the delivery of gasses and monitoring of respiration. A range of techniques are used to measure gas volume and flow, both by direct and indirect measurement. Direct methods of gas volume measurement tend to be large and impractical. By using physical properties of gases indirect measurements can be made. Understanding the principles of these techniques allows interpretation of the data they produce. Descriptions of devices used in anaesthetic practice are given. These devices include the variable orifice flowmeter, differential pressure flowmeter, hot wire anemometer, mechanical flow transducer, ultrasonic flowmeter, Wright respirometer, Vitalograph and peak flowmeter. [ABSTRACT FROM AUTHOR]

The paper presents a case study concerning the energy balance measurements for auxiliary installations using steam from the turbine of the 330 MW energy group. Steam boilers of 330 MW power plants operate with lignite dust. The thermoelectric power plants Rovinari and Turceni are composed of 330 MW energy groups. [ABSTRACT FROM AUTHOR]

Smart signal acquisition and signal processing methods are necessary for a robust and highly dynamic mass flow measurement on basis of the Coriolis principle, which allows the direct determination of the mass flow independent of process conditions with a precision of 0.2% of reading. Optical sensors which record the movement of the flow pipe have been designed and arranged with focus on fast signal processing and low complexity for a Cramér-Rao optimal information analysis. Therefore it is possible to recognize and compensate superimposed movements of the flow pipe in all six degrees of freedom as well as aging effects of the sensor elements. This leads to an increased zero point stability and a greater flow measurement range. Several algorithms for online phase estimation like Hilbert transform, correlation, discrete-time Fourier transform and quadrature demodulation in combination with minimum phase filters are investigated to develop a system with minimal time delay. [ABSTRACT FROM AUTHOR]

Abstract: This paper studied a new type of flowmeter, the bypass flowmeter. It is suitable for large-scale pipes. The principle of bypass flowmeter is studied by analyzing flowing in parallel pipes and carrying out experiments at a modified performance test system for centrifugal pumps. The study results showed that the flowrate ratio between the main pipe and the bypass pipe is determined by the geometric structures of pipes and the flowing states in the pipes. The flowrate ratio varies greatly when the Reynolds numbers are relatively lower both in the main pipe and the bypass pipe. The flowrate ratio keeps constant when the Reynolds number in the main pipe is larger than 120000. The head loss becomes smaller when the bypass pipe is connected to the main pipe. The percentage of head loss decrease is from 7.64% to 9.34%. The results indicate that bypass flowmeter is suitable for flowrate measuring in large scale pipes. It will not cause additional head loss to the flow. [Copyright &y& Elsevier]

Abstract: The measurement of volume and flow of the gases which are used during anaesthesia and in the intensive care environment is standard in modern anaesthesia practice. This is done using both electronic and non-electronic equipment. It is essential to have a thorough understanding of the basic principles of the measurement techniques used in these pieces of equipment. This is necessary for proper interpretation of the clinical data; thus, helping directly and indirectly to improve patient care. This article deals with the flow and volume characteristics of gases and the factors affecting them that lead to different types of flows. The article then discusses the core principles of different measurement techniques that are commonly used in routine clinical practice. These measurement techniques include the spirometer, vitalograph, Wright’s respirometer, Drager volumeter, gas meter, pneumotachograph, peak flowmeter, hot wire anemometer, ultrasonic flowmeter, Venturi tube flowmeter, Pitot tube flowmeter, rotameter and mechanical flow transducer. The advantages, disadvantages and common problems associated with these measurement techniques are discussed briefly. [Copyright &y& Elsevier]

The article presents abstracts of engineering research that are collated from the "Proceedings of the 19th International Congress on Condition Monitoring and Diagnostic Engineering Management," by B. K. N. Rao, U. Kumar and A. Parida. They include "A Customer and Product Support Perspective of e-Maintenance," "Tribology As Basis for Machinery Condition Diagnostics and Prognostics" and "Agent Architecture in Condition Based Maintenance for Decision Making."

Graft flow (GF) seems to be an important prognostic predictor in distal bypass for critical limb ischemia, but previous studies have failed to clarify the association between GF and the graft prognosis. GF differs significantly among grafts, and each graft seems to have an optimal GF depending on various factors. We hypothesized that comparison between the measured GF (mGF) and optimal estimated GF (eGF) would be important in predicting graft prognosis. Herein, we aimed to develop a GF predictive equation by assessing GF determinants and to validate the equation against a clinical dataset. A total of 198 distal bypasses with vein grafts for critical limb ischemia from 2011 to 2016 were enrolled. Of these grafts, 135 normal grafts without any abnormalities on early postoperative ultrasound examination were used to develop and validate the equation. Various anatomic and patient-related factors were analyzed to detect GF determinants with stepwise selection, and the GF predictive equation was developed with multiple linear regression analysis. After developing the equation, all 198 grafts were categorized into two groups according to the equation developed based on data from the 135 normal grafts as follows: optimal flow grafts (OFGs), in which mGF > eGF – 14.6, and suboptimal flow grafts (SFGs), in which mGF < eGF – 14.6. The cutoff value of 14.6 was determined using receiver operating characteristic curves to detect graft abnormalities. By comparing OFGs and SFGs, the efficacy of the equation in predicting bypass abnormalities and graft prognosis was assessed. The GF determinants were runoff, hemodialysis (HD), diabetes mellitus (DM), and graft quality (GQ). The predictive equation was estimated as follows: GF (ml / min) = (32.9 × run - off) + (9.9 × G Q) − (13.0 × D M) − (35.1 × H D) + 12.1 (R 2 = 0.71, coefficient: runoff and GQ, 3 [good], 2 [fair], 1 [poor]; DM and HD, 1 [yes], 0 [no]). In the efficacy assessment of the equation, SFGs showed a significantly higher rate of bypass abnormalities (64.0% vs 12.2%; P <.0001), graft intermediate stenosis (10.7% vs 1.6%; P =.0071), graft critical stenosis (28.0% vs 3.2%; P <.0001), and early graft occlusion (17.3% vs 4.3%; P =.0037) than OFGs and were associated with a higher rate of revision surgery within 2 years after surgery (50.7% vs 34.2%; P =.026). SFGs also showed significantly lower primary patency rates (P <.0001) and secondary patency rates (P =.0005). GF was well-estimated with runoff, GQ, and the presence of DM and HD. A comparison between mGF and eGF, calculated with the equation, will help to detect bypass abnormalities and determine the necessity of additional intraoperative procedures and, thus, achieve optimal outcomes. [ABSTRACT FROM AUTHOR]